Today, in signal transmission inside an electronic apparatus or between electronic apparatuses, technology capable of processing or transmitting a large amount of data at a high speed (for example, in real time) is necessary. In related art, signals have been typically transmitted through an electric wire. For example, low voltage differential signaling (LVDS) has been known as a method for implementing high speed signal transmission. However, due to recent new large amounts of transmission data at high speeds, problems such as an increase of power consumption, an increase of signal distortion effects due to reflection or the like, and an increase of unnecessary radiation occur. For example, LVDS has reached a limitation when signals such as an image signal (including an imaging signal) or a computer image are transmitted in the apparatus at a high speed (in real time).
In order to respond to a problem of high speed transmission data, there is a method in which the number of wires is increased and thus a transmission rate for a single signal line is decreased due to signal parallelization. However, this method causes an increased number of input and output terminals. As a result, for example, a complicated printed circuit board or cable wire or an increase of a semiconductor chip size is necessary. In addition, an electromagnetic interference problem occurs due to transmission of large amounts of high speed data through the wire.
Problems in both of the LVDS and the method of increasing the number of wires occur due to signal transmission through the electric wire. Thus, as a method of addressing the problem due to signal transmission through the electric wire, technology in which a plastic waveguide is used and signal transmission is performed using a millimeter-wave band is disclosed in, for example, “A 12.5+12.5 Gb/s Full-Duplex Plastic Waveguide Interconnect” (ISSCC 2011 conference presentations: refer to proceedings and presentation slides).